Method and device for removing metal particles form traveling products



Jan. 28, 1964 D. E. STEM 3,119,769

METHOD AND DEVICE FOR REMOVING METAL PARTICLES FROM TRAVELING PRODUCTS Filed May 19, 1961 IN V EN TOR.

DONALD E. STEM N 4 I ATTORNEX Patented Jan. 28, 1964' 3,119,769 METHOD AND DEVICE FOR REMOVING METAL PARTHCLES FRGM TRAVELING PRGDUQTS Donaid E. Stem, 492547 Sehastopoi, Santa Rosa, Calif. Filed May 19, 1961, Ser. No. 111,2459 13 Ciaims. (Ci. 209--214) This invention relates to a method and device for removing metal particles from belt-conveyed products, or products in a continued movement.

The methods and magnetic plates heretofore used for removing metal particles from a moving layer or mass of products and particularly from belt-conveyed products, had to be mounted at a height equal to the maximum height or thickness of a product moving thereunder, which arrangement made it necessary to use very powerful and costly magnets capable of attracting ferrous particles traveling thereunder from a relatively large distance.

The primary object of this invention is to provide a method and device for removing a metal object or particles from a moving layer or mass of products, such as from products conveyed on a belt by counterbalancing a comparatively light or small magnet in relatively close proximity of the surface on which the product travels so that the spacing of the magnet can be easily changed by the product so as to follow the thickness of the layer of product passing thereunder, whereby the passage of relatively large lumps of products is permitted, yet the magnet can return to close proximity of the surface on which the product travels as soon as the surge of such larger lumps of products has passed.

Another object of the invention is to provide a method and a magnetic unit which is sanitary, and which can be made and stored and used at comparatively low cost, which is comparatively small and can be easily cleaned and maintained in a sanitary condition particularly as needed in connection with the handling of food products and chemicals.

Another object of the invention is to provide a method and a magnetic unit for positively and efficiently removing magnetic particles from products passing thereunder, which method and unit is within the cost range of the average food processor.

In general, the object of the invention is to provide a magnetic unit which will substantially conform to and follow the contour of the layer or mass of products passing thereunder, and particularly the products passing on a belt under said unit.

Another object of the invention is to provide a magnetic unit and mounting for the same in such a manner that the magnet is suspended in close proximity to a surface on which the product travels, yet it is so balanced that it can conform to and follow the contour of the product without exerting any great pressure on the product and thereby preventing the crushing of the product and obviating the problem of previously used magnets which spoiled sensitive products by reason of such crushing.

A further object of this invention is to provide a magnetic unit which is capable of attracting articles of minimum magnetic attraction, such as knives or certain tools or the like so that such articles are conveyed or carried on the magnet into an out of the way position and held there by the relative movement of the parts of the device until the operator of the particular apparatus or means on which the magnetic device is mounted has an opportunity to remove such object from the magnetic unit, thereby preventing such articles to be swept off the magnet by the product.

I am aware that some changes may be made in the general arrangements and combinations of the several devices and parts, as well as in the details of the constructionthereof without departing from the scope of the present invention as set for in the following specification, and as defined in the following claims; hence I do not limit my lnvention to the exact arrangements and combinations of the said device and parts as described in the said specification, nor do I confine myself to the exact details of the construction of the said parts as illustrated in the accompanying drawings.

With the foregoing and other objects in vew, which will be made manifest in the following detailed description, reference is had to the accompanying drawings for the illustrative embodiment of the invention, wherein:

FIG. 1 is a side of a counterbalanced magnet on a conveyor.

FIG. 2 is a side view of said counterbalanced magnet lifted by a lump of material passing thereunder.

FIG. 3 is a cross-sectional view of the conveyor under a front view of the counterbalanced magnet.

FIG. 4 is a perspective view of the counterbalanced magnet.

FIG. 5 is a fragmental view showing a modified balanced magnet.

FIG. 6 is a fragmental view of another modified form.

In general the illustrative embodiment of the method of removing metal particles from passing products particularly from material carried on belt conveyors, as herein illustrated, includes the suspension of a comparatively small magnet 1 so that it is in close proximity to the surface of the conveyor belt 2 on which the products are carried and balancing the magnet so that the magnet can be raised or lowered by the varying masses of the product and follow the contour of the layer of product passing thereunder.

In the illustration shown in FIGS. 1 to 4, the magnet 1 is supported pivotally so as to be automatically swung by the product. In order to prevent crushing of the product, such as certain food products or chemicals, the magnet 1 is counterbalanced by adjustable counterbalancing means 3 so as to be raised by a minimum variation of thickness of the layer of product without exerting damaging pressure thereon.

As the product indicated at 4 passes under the magnet 1, it very lightly raises the magnet 1 whenever a bulk or lump of product passes thereunder so as to push and swing the magnet 1 away from the surface of the belt 2 thereby maintaining the magnet in closest proximity of the surface of the belt consistent with the thickness of the layer of the product thereon.

In structural detail the magnet 1 has a stub shaft 6 extended from each end 7 thereof. The stub shafts 6 are suitably journalled in spaced arms 8.

The upper ends of the arms 8 are fixedly supported on a transverse shaft 9. The shaft 9 is journalled in bearings 11 extended from brackets 12. Each bracket 12. has a base flange 13, as shown in FIG. 3, suitably attached to the frame 14 of the conveying apparatus or some other stationary'surface. In this illustrative embodimentthe frame 4 supports the conveyor belt 2.

One of the shafts 9 extends beyond the adjacent bracket 12 and has fixed thereon the hub 16 of a counterbalance lever 17 on which latter is adjustably supported a counterbalance weight 18. The counterbalance weight 18 is so spaced from the pivot shaft 9 and is of such weight that the magnet 1 is barely balanced and bears very lightly on the product 4 passing thereunder. The posit-ion of the counterbalance weight 18 on the lever 17 is adjustably held by a set screw 20.

Between the magnet arms 8 and adjacent to said magnet 1 there is provided a collector pan 19. This collector pan 19 in the present illustration is a metal sheet extended from one arm 8 to the other and has its ends bent at right angles into securing flanges 21. The free edges of the flanges are turned back into a loop 22 so as to embrace the respective arms 8. In this manner the pan 19 is supported in an inclined position along the magnet 1 and collects magnetic particles that may be attracted to the surface of the magnet as it is rotated by the product. The magnet 1 and particularly its end stub shafts 6 are lightly journalled for free rotation so that a very slight frictional engagement between the product and the magnet periphery will cause the magnet to rotate.

Even when a very slightly magnetic object, such as a knife or a tool, is attracted, it is carried around by the magnet 1, and it is lodged in the pan 19 and is thus prevented from being carried with the product on the conveyor beyond the magnet 1.

In the modified form shown in FIG. 5, the magnet 1 is supported on the arms 8 as in the first described form, but at least one of the brackets 12 has a top member 23, extending generally toward the direction of travel of the conveyor and spaced above the conveyor. A coil spring 24 has its lower end anchored on the adjacent arm 8 at the stub shaft 6. The upper end of the coil spring 24 is anchored on the end of an anchor screw 26. The anchor screw 26 extends through the top member 23. A wing nut 27 on the upper end of the anchor screw 26 bears against the top member 23 and holds the screw under predetermined tension so that the magnet 1 and the arms 8 are substantially balanced in a suitably spaced position relatively to the surface of the conveyor.

In the modified form shown in FIG. 6, the magnet 29 is of substantially rectangular cross-section and it does not rotate although it is swingable about its stub shafts 31 in the arms 8. This magnet 29 is provided with a shoe 32 on its bottom or lower side. The shoe 32 extends beyond the magnet in both directions parallel longitudinally with the conveyor. The extended portion of the shoe 32 in the direction from which the product approaches is curved or turned upwardly to form a curved edge 33 at such angle as to facilitate the lifting of the magnet by a lump of product travelling thereunder. The other edge 34 of the shoe 32 extending toward the direction of the flow of the product is also slightly turned and rolled so that magnetic particles are collected on the bottom face of the shoe 32 and such particles that are swept along said face of said shoe 32 by the product, collect along the edge 34 of the shoe 32 and are held thereby out of the product.

In each form herein described, the magnet is comparatively small and light. The magnet is suspended and then the counterbalance is adjusted so as to barely balance the magnet at suitably spaced relation to the surface of the product passing thereunder in an initial position. The magnet is thus easily movable away from said surface by the thickness of the product passing thereunder without crushing the product. In the form shown in FIGS. 1 and the magnetic particles or objects are carried around by the magnet as it is rotated by the conveyed product and are collected in the pan 19. In the form shown in FIG. 6, the magnetic particles are collected at the rolled edge 34 of the shoe as heretofore described.

I claim:

1. The method of removing magnetic particles from traveling product such as conveyed products, comprising the steps of conveying the products on a surface and supporting a magnet in a stationary position relatively to the travel of said products but yieldably relatively to said surface so that the magnet is above said surface on which the products travel so as to be raised by a minimum variation of thickness of product traveling thereunder, attracting magnetic particles from said product to said magnet, and holding the attracted magnetic particles on said magnet separated from said product.

2. The invention defined in claim 1, and predetermining the initial position of said magnet relatively to said product by counterbalancing said magnet with minimum resistance to said raising by said product.

3. In a device for the removal of magnetic particles from a moving layer of products moving on a surface, a magnet, means stationary relatively to the movement of said layer to support said magnet in predetermined proximity to said surface and adjustably toward and away from said surface on which said product travels, and means to counterbalance said magnet so as to predetermine the initial spacing of the magnet above said surface and its resistance to movement by said product.

4. In a device for the removal of magnetic particles from a layer of moving product defined in claim 3, and the weight and leverage of said counterbalancing means relatively to said magnet being predetermined so as to counterbalance nearly the entire weight of said magnet.

5. In a device for the removal of magnetic particles from a layer of moving product defined in claim 4, and adjustable means on said support means to adjust said counterbalancing means to said predetermined counterbalance.

6. In a device for the removal of magnetic particles from a layer of moving product defined in claim 3, relatively stationary means adjacent said magnet to collect and hold the attracted magnetic particles out of the way of said moving product.

7. In a device for the removal of magnetic particles from a layer of products moving on a surface, a magnet adapted to extend transversely across above said surface on which said layer of product moves, a relatively stationary frame, adjustable means on the frame to support said magnet above and in transverse relation to the movement of said products, and counter-balancing means coacting with said adjustable means to counterbalance said magnet in said initial position.

8. The invention defined in claim 7 and means to rotatably support said magnet in said adjustable supporting means.

9. In a device for the removal of magnetic particles from a moving layer of products defined in claim 8, and a collecting pan extended substantially tangentially along said rotatable magnet along the side of the magnet facing in the direction from where said products move.

10. The invention defined in claim 8, wherein said frame extends to above the level of said layer of products, said adjustable supporting means include supporting arms pivotally held on said frame, and said counterbalancing means being adjustably connected to said supporting arms.

11. The invention defined in claim 10, wherein said counterbalancing means include a counterbalancing arm extended from and connected for movement with said supporting arms about the pivot of said supporting arms, and an adjustable weight on said counterbalancing arm.

12. The invention defined in claim 10, wherein said counterbalancing means include a coil spring, one end of said coil spring being anchored on one of said supporting arms, and the other end thereof on said frame so as to urge said supporting arms to turn toward the direction of movement of said products.

13. The invention defined in claim 7, wherein said magnet is swingable on said frame, a shoe along the bottom of said magnet spaced from said products, the edge of said shoe nearest to the approaching product being curved upwardly and away from said product for gradual engagement by projecting masses of said product for swinging and lifting said magnet.

References Cited in the file of this patent UNITED STATES PATENTS 

1. THE METHOD OF REMOVING MAGNETIC PARTICLES FROM TRAVELING PRODUCT SUCH AS CONVEYED PRODUCTS, COMPRISING THE STEPS OF CONVEYING THE PRODUCTS ON A SURFACE AND SUPPORTING A MAGNET IN A STATIONARY POSITION RELATIVELY TO THE TRAVEL OF SAID PRODUCTS BUT YIELDABLY RELATIVELY TO SAID SURFACE SO THAT THE MAGNET IS ABOVE SAID SURFACE ON WHICH THE PRODUCTS TRAVEL SO AS TO BE RAISED BY A MINIMUM VARIATION OF THICKNESS OF PRODUCT TRAVELING THEREUNDER, AT TRACTING MAGNETIC PARTICLES FROM SAID PRODUCT TO SAID MAGNET, AND HOLDING THE ATTRACTED MAGNETIC PARTICLES ON SAID MAGNET SEPARATED FROM SAID PRODUCT. 